Air tube for pneumatic tires



June 19, 1923.

T. B. M LEROTH AIR TUBE FOR PNEUMATIC TIRES Filed June '16 1920 5Sheets-Sheet 1 June 1%,

T. B. M LERO R PNEUMATIC TIRES 3 Sheets-Sheet 2 Filed June 16 1920 v All i u T. B. MCLEROTH A'IR TUBE FOR fNEUMATIc TIRES Filed June 16 1920 3Sheets-Sheet 5 FIG. /0.

FIG. 9

FIG. /5.

FIG. /2.

Patented aim is, was.

UNHT'D stares arana. at.

THOMAS BER MOLZEROTH, OF LONDON, ENGLAND, ASSIGNOR TO T. B. MOLEROTH(TUBES) LIMITED, OF LONDON, ENGLAND, A BRITISH COMPANY.

am TUBE ron PNEUMATIC Trans.

- Application filed June 16, 1920,. Serial No, 389,293.

To all whom. it may concern:

Be it known that I, THOMAS BAKER Mo- LEnoTH, of Barholm, 346 CamdenRoad, London, N. 7, England, a subject of the King of Great Britain andIreland, have invented certain new and useful Improvements in ,Air Tubesfor Pneumatic Tires, of which the following is a specification.

This invention relates to an air tube for pneumatic tires of the kindcomprising a plurality of sections or compartments so arranged that thepuncturing of one section or compartment will not materially affect theefficiency of the tire as a whole.-

According to this invention an air tube for pneumatic tires is composedof a series of sectionsor compartments formed by partitions, into eachof which sections or compartments leads an apertured projection normallyconnected with a passage running around the inner periphery of the tubesaid passage being provided with a valve for inflation purposes. Thetube is referably made in a length and the wall 0 each section orcompartment is split or otherwise apertured to enable the core for saidcompartment to be withdrawn therefrom, and said aperture may be closedby a band or series of patches applied to said tube after the ends of alength of the tube have been joined to constitute an annulus.

The mould may be constituted by a tube formed in three parts, onecorresponding with what will be the tread or outer periphery, and thetwo others with what will be the sides and inner periphery of the tubeand the two last mentioned parts are hinged to the first mentioned partand are adapted to be clam ed together at their free edges.

Preferab y, also, the cores for the sections or compartments are adaptedto be slidden successively into position in the mould, and each core ismade in sections and ada ted to be contracted, each core or the moulbeing so formed as to tread portion 0 the section or compartment,through which aperture the contracted core may be withdrawn.

The invention is illustrated by the accomanying drawings wherein Figure1 is a ragmentary section-of one form of air tube,

on the line 11, Figure 2 Figure 2' is a cross-section on the line L2,Figure 1, Figure 3 is a similar cross-section of another produce anaperture in the form of air tube, Figure 4 is a section of a mould onthe line 4-4, Figure 5, Figure 5 is a cross section of the mould on theline 5-5, Figure 4, Figure 6 is aside elevation and F igure 7 is a planof a core, Fi ure 8 is a sectional plan on the line 8-8 'igure 4, Figure9 is an end View of a central section of a core, Figure 10 is an endview of the contiguous face of an outer section of a core, Figure 11 isan end view of the outer face of another form of outer section of acore, Figure 12 is a sideelevation of a core in its contracted positionand Figure 13 is an end view of a contracted core shewing the open mouldin section.

As shewn in Figures 1 and 2 the air tube consists o f a plurality ofcompartments a formed by partitions b in a tube 0, into eachof whichcompartments a leads a thin rubber tube (1 normally connected with apassage 6 running aroundthe inner periphcry of the tube 0 and providedwith a valve f for inflation purposes. Each of the compartments a is ofsubstantially D-shape in cross-section and occu ies the greater part ofthe cross section 0 the tube 0, and the passage 0 is of similar shapeand occupies but asmall part of the cross section of said tube.

;\In the form illustrated by Figure 3 the passage e instead of beingformed in the tube 0 itself isformed by a separate portion 9 adapted tobe secured to said tube by india rubber solution or the like.

The mould illustrated is adapted for the production of a tube 0 of asection such as is illustratedby Figure 3 and is constituted by a tubeformed in three parts h, and j, j,

' the part 71, corresponding with what will be the tread or outerperiphery of the tube 0 to be produced, and the parts j, j correspondingwith what ,Wlll be the sides and inner p riphery of said tube, and theparts 7', are hinged as at k, is to the part it and are adapted to beclamped together at their free edges by any convenient means (notshewn).

At its inner surface the part it of the mould is formed with an undercutperipheral groove as at m, Figures 5 and 13, adapted to receive lugs 71.on the cores for the several compartments a whichcores may be sliddensuccessively into position. after the necessary india rubber has beensuitably disposedin the mould according to the method of manufacture.As' shewn in Figures .part it of the mould so as to produce an aperturein the tread of the tubec. The contiguous faces of the central and outerparts 17 and 0, g of the core are inclined to the axis of the core,convergin towards the inner periphery of the moul as shewn in Figures 4,6 and 12 and said parts are 'slidably interconnected by forming the endfaces of the part with dovetailed tongues s, s and the contiguous facesof the parts 0 and q with corresponding grooves 25, t. The tongues 8, sare slotted as at u, almost to the inner ends thereof and the parts 0and r are provided, in the grooves t, t, with stops, as at '2), adaptedto be received in the slots u and to engage the closed inner endsthereof. The construc-.

tion is such that as the mould is drawn away from the inner periphery ofthe tube 0 the central part of the core is first withdrawn as shewn inigures 12 and 13, drawing the outer parts 0, 9 towards one another andthus contractin the core, and the outer parts 0, g are t en withdrawn asone with the central part p.

The outer end faces of the parts 0 ..are

' made concave and the outer end faces of the parts g are made convexfor a purpose to be referred to hereinafter.

As shewn at the left hand side of Figure 4, the part q of each core isformed with a bore w radially ofthe mould and debouching at the innerperiphery of the tube 0 to be formed, and in said bore w is coaxiallydisposed a fine wire a: projectingtherefrom and adapted to extendbetween the freeedges of the parts j j of the mould when said mould isclosed as shewn in Figures 4 and 5, the bore 20' and wire in beingadapted to form the fine rubber tube 03 leadin into the compartment a.The right ham side of Figure 4, and Figure 11 illustrate different meanswhereby the fine tubes (Z may be produced integrally with the partitionsb. For this purpose instead of forming each part I with a bore '11; theouter face of each part 0 is formed with a groove 1 of semi-circularcross-section extending to the inner edge of" said part, and coaxiallywithin said groove is disposed a fine wire ac adapted to extend as aboveset forth and curved to conform with the configuration .of the outerface of the part 0. Cores'of the construction shewn in Figs. 5 to 1O maybe used in the same mould in conjunction with cores of the i oeeM typeshown in Fig. 11, such joint use of both kinds of cores beingillustrated by Fig. 4. With a mould such as shewn in Fig. 4, the airtube produced will be substantially of the character represented in Fig.1.

A According to one method of manufacture the parts j, j ofthe mould areswung open as indicated in dotted lines in Figure 5, india rubber isplaced inposition in the mould and around a core 0, p, ,the lug n ofanother core 0, p, q is slid en into the roove m and said other core issurrounde with closed and the tube is vulcanized in the usual manner,the narrow slit left between the free edges of the parts j, j of themould, due to the projection of the wires :12 therebetween providing anoutlet for the spewing over of the rubber in the usual manner.

After vulcanization is complete the parts j, j are swung open and themould is drawn away from the tube 0, all the cores being simultaneouslycontracted and then withdrawn from the several compartments a throughthe apertures z in the tread of the tube 0, the wires on beingsimultaneously withdrawn from the fine tubes d A length oftube soproduced is then joined up at its ends in the usual manner to constitutean annulus and a tread band 21 or a series of patches is or are appliedto through which close the apertures z the cores were withdrawn. Anotherband 9 is then applied at the inner periphery of the tube 0, beingattached at its edges only so as to form a common air passage e witwhich communicate all the fine tubes 03 In order to produce a tube a ofthe cross- .section shewn in Figure 2, the parts 0, p

and 1 of the cores are made D-shaped, the

fiat side being situated remote from the part h of the mould. Means,such as described above, are provided for producing the fine' tubes (1but the wires :0 do not project so far as the junction of the parts j, jof the mould, but are adapted to engage apertures in a core, in the formof a rod of D-section for the air passage e which is common to all thecompartments (1 If desired said D-section rod may be formed of aplurality of short lengths strung on a wire or the like, so that one ofsaid lengths may be slidden into position as and when each core is soplaced and so that the totality of such lengths may be withdrawn as oneaxially from the passage e by pulling on 'india rubber and so on, Themould is then the .wire or the'like, after the mould has been opened andthe cores withdrawn thus face of the part k of the mould, but it ispreferable that they should be on the cenin the treadof the tube gmay beprovided on the inner tral parts p of the cores so as to ensure correctpositioning.

It is desirable that the outer faces of the parts 0 and g of the coresshould be made concave and convex as above set forth so that when thetube 0 is fully inflated in use the diaphragms a may be slack, that isto say, may not be in tension.

When a tube made in accordance with this invention is beinginflated airpasses through the passage 6 and fine tubes d to all the compartments athe pressure being equally distributed throughout. In the event of thepuncture of any compartment a the reduction of pressure thereinconsequent upon the escape of air therefrom permits the diaphragms 6-?)on either side thereof to belly out towards one another due to thepressure acting thereon and this bellying out causes the fine tube (Z inthe punctured compartment to be bent over thus breaking Off theconnection with said compartment of the passage e and preventing furtherescape of'air. The diaphragms Z; separating the remaining compartments aall belly out slightly towards the punctured compartment so that thepressure within the tire is once more equally distributed and thepuncturing of the compartment will not materially aflect the efliciencyof the tire as awhole.

It will be observed that each of the compartments a, as long as it isnot punctured, has a free communication, through the corresponding tubed, with the circumferential passage e, so that air may pass through saidtube freely in either direction as long as the particular compartment isnot punctured. This is of importance not only bypermitting the severalcompartments to be inflated simultaneously through a single inflatingvalve 7 connnected with said passage or channel 6 but equally in case itis desired to deflate the air tube for the purpose of removing it, forinstance in order to repair the tube after a puncture. In the event of apuncture, as explained above, the tube (2 of the punctured compartmentwill be bent by the bellying out of one or .both diaphragms 7) of suchcompartment, sufficiently to close the channel of such tube and thusinterrupt communication between the passage or chan- While the inventionhas been described and claimed as an air tube for pneumatic tires, itwill be obvous that a tube embodying the features of this inventionmlght serveas a so-called single tube tireyand I desire the claims to beinterpreted as covering this use.

I claim r 1. An air tube for pneumatic tires having a series ofpartitions dividin said tube into a series of compartments, a ne rubbertube in each of said compartments adjacent to one of saidpartitions,'said air tube being formed with a passage running around theinner periphery thereof and said passage communicating with saidcompartments through said fine rubber: tubes and being provided with aninflation valve.

2. An air tube for pneumatic tires having a series of partitionsdividing said tube into" a series of compartments and adapted to bebellied out into a punctured compartment, a flexible rubber tube in eachcompartment, in the ath which a partition of such compartment willfollow in the event of such compartments being punctured, so that thebellied-out partition of the puncture compartment will come in contactwith said flexible tube, and bend it to close the passage of suchflexible tube, said air tube being further formed -with a passage runninaround the inner periphery thereof an normally communicatin with saidcompartments through said flexi le rubber tubes and being provided withan inflation valve.

3. An air tube for pneumatic tires having a series of partitions dividinsaid tube into a series of compartments, a ne rubber tube in each ofsaid compartments, a band se= cured at its edges to the inner peripheryof said tube and forming a passage therearound, said passagecommunicating with said compartments through said fine rubber tubes andbeing provided with an inflation valve.

4:- An air tube for pneumatic tires having a series of partitionsdividing said tube into a series of compartments, said partitions beingslack when said tube is fully inflated, a fine rubber tube in each ofsaid com artments' adjacent to one of said partitlons, said air tubebeing formed with a passage running around the inner periphery thereofand said passage communicating with said compartments through said finerubber tubes and being provided'with an inflation valve.

5. An air tube for pneumatic tires having an inflating channel providedwith an inflation valve, a series of partitions dividing said tube intoa series of compartments and adapted to be bellied-out into a puncturedcompartment, said partitions being slack when the tube is fullyinflated, a connection in each compartment normally affording opencommunication between such compartment and the inflating channel, saidconnection belng in the path which the partition follows upon thepuncturing of the compartment so as to cause the partition to effecttheclosing of the connection.

6. An air tube for pneumatic tires having a series of partitionsdividing said tube into a series of compartments and adapted to bebellied out-- into a punctured compartment, said partitions being slackwhen the tube is fully inflated, a flexible rubber tube in eachcompartment, in the path which a partition of such compartment willfollow in the event of such compartments being "punctured, so'that thebellied-out partition of the punctured compartment will come in contactwith said flexible tube and bend it to close the passage of suchflexible tube, said air tube being'further formed with a passage runningaround the inner periphe thereof and normally communicating witl i saidcompartments through said flexible rubber tubes and being provided withan inflation valve.

THOMAS BAKER MCLEROTH.

